For the purposes of mtools, all MS-DOS file names begin with a drive letter and colon, followed by the path. mtools accepts both / and \ for directory separators. For example, an MS-DOS file might be referred to as a:/directory/subdirectory/file.txt. If you use the backslash or any standard Unix wildcards or special characters, put the filename in quotation marks.

FAT filesystem filenames are normally a maximum of eight characters long with a three-letter extension, and are not case-sensitive. Even in the more recent VFAT system, which does preserve case sensitivity, two files with the same letters in their names, regardless of case, cannot coexist. Unix filenames that are too long, that use reserved characters (; + = [ ] ' , \ " * \ \ < > / ? : or |), or that conflict with MS-DOS devices (PRN, for example) are converted to VFAT names. This means replacing reserved characters with an underscore (_) and shortening files as needed, replacing several characters with a single tilde (~).